do we need redis cache in nextjs app because route caching is already available

Incorporating Redis or any external caching solution into a Next.js application, despite Next.js's built-in support for route caching, depends on the specific requirements and architecture of your application. Here’s a breakdown of considerations to help you decide whether integrating Redis for caching is beneficial for your Next.js project:

Next.js Built-in Caching

Next.js offers automatic, per-route caching in its server-side rendering (SSR) and static generation features, which can significantly improve performance by reducing the need to re-render pages on each request. This caching is mainly for the HTML output of pages.

When Redis or External Caching Might Be Needed

1. Session State Caching:

If your application manages session states or user-specific data, using Redis as a session store can be more efficient and scalable than relying on in-memory or database storage, especially in environments where your application scales horizontally across multiple instances.

2. API Response Caching:

For applications that heavily rely on external API calls, caching these responses in Redis can drastically reduce latency and API rate limit consumption. While Next.js can cache the output of these API calls indirectly through its page caching, direct control over API response caching can provide more granularity, such as caching specific API requests independently of the page requests.

3. Real-time Data:

Applications that require real-time data processing and delivery might benefit from Redis beyond simple caching. Redis pub/sub capabilities support real-time messaging patterns which are not directly related to caching but can enhance the functionality of a Next.js app.

4. Complex State Management Across Routes:

If your application’s state management involves complex interactions across multiple routes, Redis can offer a centralized state management solution that is consistent and quickly accessible from anywhere in your application.

5. Rate Limiting:

For applications that need to implement custom rate limiting on certain actions or API requests, Redis is an excellent choice due to its ability to expire keys and increment counters atomically, which are essential features for efficient rate limiting implementations.

6. Large Scale and High Traffic Scenarios:

While Next.js’s built-in caching works well for many scenarios, high-traffic applications might need the additional caching layer that Redis offers, especially to handle data that isn’t efficiently cached at the HTML level or to reduce database load.